This season will saw a group of demons gang up on the hero of the south any other time is because they would kill them before they had any chance to retaliate. The next major arc will show a demon who essentially has an insta-kill ability that needed years and years of planning to beat.
Demons fight mages 1-on-1 because they prefer to pick off normie villagers on their own and accidentally run into mages in the process. It doesn't take more than 1 demon to eat a village (if there isn't a mage there) and teaming up means splitting the spoils.
The last demon that tried to organize beyond that was killed in his home by a hit-squad of foreign adventurers, so demonkind is a bit wary of the concept.
How is it always without fail the same cadence and voice acting every time?
Does no one listen back to the recordings and think they should do retakes?
Kuma to Usagi wa Tomadachi, the big tanned guy everyone thinks is a sleazy playboy delinquient based on looks is actually just a softy who wants to make buddies, and the woman who reaches out to be his buddy is a total pervert who has sex on the mind 90% of the time. Predictable hijinks ensue.
I just learned that Scum of the Brave is by the same author that did Sentenced to Be a Hero. Weird having 2 seasonal anime of the same guy. Wouldn't be surprised that Scum of the Brave would last longer than its larger budget brother due to more meme potential.